Investigations on the role of the salmon louse, Lepeophtheirus salmonis (Caligidae), as a vector in the transmission of Aeromonas salmonicida subsp. salmonicida

Abstract A bacteria–parasite challenge model was used to study the role of sea lice, Lepeophtheirus salmonis (Copepoda), as a vector of Aeromonas salmonicida subsp. salmonicida . Three hypotheses were tested: (i) L. salmonis can acquire A. salmonicida subsp. salmonicida via water bath exposure; (ii)...

Full description

Bibliographic Details
Published in:Journal of Fish Diseases
Main Authors: Novak, C W, Lewis, D L, Collicutt, B, Verkaik, K, Barker, D E
Other Authors: Natural Sciences and Engineering Research Council of Canada
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2016
Subjects:
Online Access:http://dx.doi.org/10.1111/jfd.12449
https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjfd.12449
https://onlinelibrary.wiley.com/doi/pdf/10.1111/jfd.12449
Description
Summary:Abstract A bacteria–parasite challenge model was used to study the role of sea lice, Lepeophtheirus salmonis (Copepoda), as a vector of Aeromonas salmonicida subsp. salmonicida . Three hypotheses were tested: (i) L. salmonis can acquire A. salmonicida subsp. salmonicida via water bath exposure; (ii) L. salmonis can acquire the bacteria via parasitizing infected Atlantic salmon, Salmo salar and (iii) L. salmonis can transmit the bacteria to naïve Atlantic salmon via parasitism. Adult L. salmonis exposed to varying A. salmonicida subsp. salmonicida suspensions (10 1 –10 7 cells mL −1 ) for 1.0, 3.0 or 6.0 h acquired the bacteria externally (12.5–100%) and internally (10.0–100%), with higher prevalences associated with the highest concentrations and exposures. After exposure to 10 7 cells mL −1 , viable A. salmonicida subsp. salmonicida could be isolated from the external carapace of L. salmonis for 120 h. Lepeophtheirus salmonis also acquired the bacteria externally and internally from parasitizing infected fish. Bacterial transmission was observed only when L. salmonis had acquired the pathogen internally via feeding on ‘donor fish’ and then by parasitizing smaller (<50 g) ‘naive’ fish. Under specific experimental conditions, L. salmonis can transfer A. salmonicida subsp. salmonicida via parasitism; however, its role as a mechanical or biological vector was not defined.